A cipher which uses a different encryption key every time, as long as the message. The key is XOR'ed with the message to render the cipher text which can then be XOR'ed with the same key to get the plain text.

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Present an attack for the combination of OTP and textbook RSA

Let $N=p \times q$ where $p$ and $q$ are two primes. Compute $\Phi (N) = (p-1)(q-1)$. Choose $e$ s.t. $1 < e < \Phi(N)$ and $gcd(e,\Phi(N))=1$. Compute $d = e^{-1}(mod \ \Phi(N))$. ...
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1answer
222 views

Hash functions to generate one time pad

Newbie question... may be... Stream cypher, will XOR message bits with one time pad bits Suppose I have a pseudo random number generator, like a Mersenne twister or sort of. I could use the ...
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1answer
110 views

Is one-time-pad still secure if the number of 1's in the key is revealed to the attacker?

For example, if $m = 10011$, $k = 11001$, $n=3$ (which is the number of 1's in k), $c = m \oplus k = 01010$. If $c$ and $n$ are revealed to the attacker, is this scheme still secure?
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2answers
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If you have a file and XOR every bit with a random bit, can you extract any information?

Say you have a file that is not random, and you XOR every bit with a random bit (not pseudo, but really random). Can someone who sees only the result extract any information from it? Obviously, it ...
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1answer
108 views

Will adding space to the Vigenère block make it truly unbreakable?

I just have gotten into cryptography and learned about the Vigenère block. I think it's a very good idea because, if used correctly, it is unbreakable. But the only downsite is, the key must be the ...
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4answers
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Is the one-time-pad a secure system according to modern definitions?

Occasionally I hear people say that one-time pads are "useless" or even "broken". "modern cryptography knows more security definitions, under some of which the one-time pad is completely ...
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2answers
118 views

Sending the next one-time pad key in this one-time pad message? [duplicate]

I am doing a research project on cryptography next year, and I'm really new to cryptography. This isn't some really advanced thing or anything, and I'm just trying to come up with something basic. ...
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1answer
104 views

Is this adaptation of one-time-pad still secure?

Having shared a pad of length double the length of your anticipated message, splitting it into x and y. Then using x to encrypt the message, and using y twice to encrypt the next pad, would that be ...